Barack Obama addressed what he described as the public "ruckus" over the leaked National Security Agency surveillance documents on Monday, indicating that the US authorities would pursue extradition from Hong Kong of the whistleblower Edward Snowden.

In his first public comments in 10 days about the NSA disclosures, Obama also said he had set an oversight board made up of independent citizens and the ordered the declassification of documents relating to surveillance to allow the public to see the broader context.

The president, who is attending the G8 summit in Northern Ireland, was speaking on PBS's Charlie Rose programme. Asked about Snowden, who remains free in Hong Kong and who took part in an online Guardian Q&A on Monday, the president said: "The case has been referred to the DOJ for criminal investigation … and possible extradition. I will leave it up to them to answer those questions."

Any request for extradition – technically a "surrender" in Hong Kong – would normally be the decision of the territory's government. Snowden would be able to challenge it through the Hong Kong legal system, although lawyers think he would probably be unsuccessful in the end. In theory, Beijing could step in to stop him being sent back, but it would be unlikely to relish an all-out public row with the US. Obama did not offer any more details about the process in his PBS interview.

Instead, he addressed criticism that he has shifted a long way from the liberal positions he championed during his 2008 White House race, and denied that he had adopted the surveillance regime put in place by the previous administration "lock, stock and barrel". Obama said: "My concern has always been not that we shouldn't do intelligence gathering to prevent terrorism, but rather are we setting up a system of checks and balances."

The president said it was a "false choice" to say that American freedoms needed to be sacrificed in the goal of national security. "That doesn't mean that there are not tradeoffs involved in any given program, in any given action that we take. So all of us make a decision that we go through a whole bunch of security at airports, which when we were growing up that wasn't the case … To say there's a tradeoff doesn't mean somehow that we've abandoned freedom." He added that it was his job to "make sure that we're making the right tradeoffs".

Obama praised the professionalism of the NSA and insisted that it did not listen to the phone calls or read the emails of US citizens. Only the FBI had that power, and then only with a warrant.

The president conceded that while he was confident the necessary system of checks and balances was in place, the public might not fully be aware of this. "What I've asked the intelligence community to do is see how much of this we can declassify without further compromising the program."

He also disclosed that he had set up an "oversight board" to examine the issues of privacy. "I've stood up a privacy and civil liberties oversight board, made up of independent citizens including some fierce civil libertarians. I'll be meeting with them." He did not give any further details about the board.